Telephone system



H. P. CLAUSEN ANDC. L; 6000mm.

TELEPHONE SYSTEM. APPLICATION HLED MAY H. 1918.

Patented-Apr. 12, 1921.

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UNITED STATE- S PATENT OFFICE.

HENRY P. CLAUSEN, OF MOUNT VERNON, AND CHARLES L. GOOIDRUM, OF NEW YORK, N. I, ASSIGNORS TO WESTERN ELECTRIC COMPANY, ZENCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Application filed May 11, 1918. serial No. 233,970.

To all whom it may concern:

Be it known that we, HENRY P. CLAUSEN and CHARLES L. GoonnUM, citizens oi the United States, residing at Mount Vernon, in the county of lVestchester, State of New York and at New York in the county of New York, State of New York, respectively, have invented certain new and useful Improvements in Telephone Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone systems and more particularly to those in which inter-oflice or inter-city trunk line circuits are employed.

In such systems, it is a common practice to build up or complete a sectionalized trunk line for telephonic communication between two widely separated switching centers or stations by joining together through suitable connecting means at various intermediate switching centers or stations, the normally independent trunk circuits interconnecting such intermediate stations.

It is the object of the present invention to provide an improved signaling arrangement for use in connection with such. systems whereby the building up of such sectionalized trunks will be greatly expedited, due to the fact that the operators at the various stations may readily determine the status of the various interconnecting trunk circuits.

To attain this object in accordance with a feature of this invention, means is provided at each switching center or station, which is operative when all trunks between that and some other station are contemporaneously engaged, to automatically convey such information to operators at other stations, thus eliminating the necessity of the originating operators ascertaining from each of the affected operators whether the desired trunk linesare engaged.

i The nature of the invention will be more clearly understood from the following speci fication and the annexed drawing in which the figure shows diagrammatically several trunk lines normally joining the intermediate stations, and a typical connecting or link circuit for interconnecting such trunks at the stations. i

In the drawing, the switching center or station A isjoined with station B by means of trunk circuits F and I. The station B is joined with station C by trunk circuit G and with station D by trunk circuit J, while station 0 is joined with station D by trunk circult H. in each case, it is understood that although only a few trunk lines are shown, a plurality of each class of such trunk lines may join the respective stations. Several link or connecting circuits- E of any suitable type may also be furnished at each station torintercoimecting the trunk circuits terminating thereat. Eac-htrunk terminal is provided with a jack and a sleeve relay, such as jack 7 and relay 8 of the trunk circuit F, for cooperation with the plugs 1 and a of the cord circuit E. At each station, various signaling devices, such as 10, are controlled by associated relays, such as 9, to indicate to the operator at such station the status of portions of the sectionalized trunk line interconnecting other stations.

It is believed that the invention will; be

more fully comprehendedfrom the following description of the operation thereof.

Assuming that at station A, the plug 4: of the cord circuit E is inserted in jack 7 of trunk circuit-F, the relay Soperates and the lamp 5 lights over a circuit established from battery through lamp 6, resistance 5, sleeve contactsof plug 4 and j acl: 7, and winding of relay Sto ground. If the plug 4: of another cord circuit E at station A is contemporaneously connected with jack 25 of trunk circuit I, relay 26 is operated in a similar manner, whereupon, due to the serial rela tion of the contacts of relays 8 and 26, relay 31 is operated over a circuit established from battery through the winding of relay 31, ring conductors of trunk circuits J and I, and contacts of relays 26 and 8 to ground. Lamp 32 is thereupon lighted over a circuit from battery through the contact of relay 81 and lamp 32 to ground, to notify the operator at station C that trunk circuits .1? and I are engaged. Relay 33 is also operated over "a circuit extending from battery through the winding of relay 33 to the ring conductor of trunk circuit J where it joins the operating circuit of relay 31. By the consequent lighting of lampi i over a circuit from battery through the contact of relay 33a11d lamp 3% to ground,theoperator at station D also is notified that the trunk circuits F and I are engaged. It is evident that other trunk circuits similar to trunk Patented Apr. 12, 1921. v

circuits F and 1 connecting stationsA and B the contacts 01" the sleeve relays in series'relation with the corresponding o'l' relays 8 and 26, the engagement of all such trunk circuits would ca se the li hting ct lamps 32 and 8a in a similar manner.

Similarly upon the insertion of plug 1 of cord circuit it located at station E in jack 11 of trunk circuit F, relay 12 operates and lamp 3 lights over a circuit from battery through lamp 3, resistance 2, sleeve contacts of plug 1 and jack 11 and winding of relay 12 to ground. When another similar link circuit is also connected with the trunk circuit 1, by'the insertion of plug lin jack 2?, relay 28 operates over a circuit similar to the operating circuit of relay 12, and due to the serial connection of the contacts of'rclays 12 and 28, ground is thereby connected to the ring conductors of trunks land J to cause the operation oi relays 81 and 33 and the consequent lighting of lamps and 3 1" as prev1ouslydescribed. lhus a 00111180131011 made with either terminal of all of the trunk circuits such as F and I joining stations A and causes the display of signals at stations C and D r 1i cord circuits similar to E are connected with trunk circuits G and J at station'lfi, by means of plug l'inserted in jacks 13' and 29 respectively, relays 11a and 30 operate in the manner 'describedfor relays 8 and 26, and ground will be. connected to the ring con ductor of trunk circuit J, due to the serial relation otthe left-hand contacts or" relays 1 1 and 30, thereby causing the operation of relays 31 and 83 and the consequent lighting oflamps 32 and as before. Relayl, in operating, also completes a circuit from battery through thewinding '2 relay 9, ring conductor of trunk circuit 1* and right-hand contacts of relays 14 and 30 to ground. Relay 9 thereupon operates,causing the lightin of 1am at station A over'a circuit b froinbattery through the contact ofrelay 9 and lamp 10 to ground. The lighted conditionoilamp 10 serves to automatically indicate to the operatorat station A that trunk circuits G and J are engaged. 7

In case cordfcircuit E is connected With trunk circuit G at station 0 by the insertion of plug 1 in jack 1?, relay 18 operates inthe manner described for relay 8. By the olo. sure of its right-hand contact, relay 18 establishes a circuit from battery throu h the winding of relay 22, tip conductor 01' trunk c1rcu1t H and the right-hand contact of re lay 18 to ground. Relay 22 thereupon opcrates, lighting the lamp 21 over a circuit from battery through the contact oirelay 22 and lamp 21 to ground. Thus, the operator at station l) is notified of the engaged condition of trunk circuit Gr. lit is evident that other trunk circuits similar to trunk circuit may be'aclded and the contacts of relays simllar to relay 18 Wired in seriatz'm as shown for relays 8 and 26. In case relay 1 l J1. v ing o relay 9, the ring trunk circuitll at plug 4 of cord circuit E is also inserted in jack 13 0i the tr ircuit G at station and therefore is operated, a circuit .willf also be established from battery through the Windconductor of trunk circuit F, the right-hand contact of relay 1 1, the tip conductor of trunk circuit G and the left-hand contact of relay 18 to ground.

Bela enerates causin the li ht-inc of J r 7 a b 0 amp 10 at station A to notify the operator 'hereat that the trunlrcircuit G is engaged. cord circuit l l is connected with the truulr circuit'H at the station C by the insertion of plug in jack l9, relay operates the seine manner'as previously described a relay 8, A circuitis thereupon estabied from relay rnn conductorot trunlr circuit G A a V and the contact or relay to ground. He-

lay 15, inope icing, lights the lamp 16, over circuit troi 7y through the contact oi d lamp 16 to round, thereupon relay 15 an notifying the operator at station B that trunk circ .t'll is engaged.

similar trunk circuits may beadded byserially interconnecting the contacts of the respective sleeve relays.

In case cordcircuit E is connected with station 1) by the inserot plug 1 in jack 23', relay 2% operates in manner cescribed for relayS, and a circuit is completed from battery through the Windin oi relay 15, ring conductors of trunk ciruits @and Hand the contact of relay 2% to ground. Relay 15 thereupon operates and,

as before, the consequent lighting of the lamp lc'indicates to'the operator at station E that trunk circuit l-l is engaged.

lt willv be evident from the above description that numerous other combinations and arrangements of" the signaling means are possible, dependent upon the arrangements of the trunk circuits joiningthe intermediate stations and the service rendered thereby.

What is claimedisz 1. In a telephone system,'a plurality of stations, a plurality of trunk circuits'interconnecting the stations, a plurality of link circuits at each station for interconnecting the trunk lines terminating thereat to form sectionalized trunk line circuit joining normally disconnected stations, and means to automatically:indicate at the normally disconnected stations the status of the trunks normally interconnecting the other stations. I

2. In a telephone system, two Widely sep arated stations, a plurality of intermediate stations, a plurality of trunk circuits. inter connecting the intermediate stations, a plurality of link circuits at each intermediate station for interconnecting the trunk cir- As mentioned d in connection With trunk circuit F, other ttery through the Winding of means for indicating at the widely separated stations when all trunk circuits interconnecting any two intermediate stations are engaged, thereby preventing the completion of a trunk line circuit between the widely sepa 'ated stations. 3. In a telephone system, a plurality of switching points, a group of trunk circuits extending from each switching point to another, a plurality of link circuits at each switching point to interconnect the trunk circuits thereat to form sectionalized trunk line circuits joining normally disconnected switching points, and signaling means at the normally disconnected switching points automatically responsive to the contempo raneous engagement of the link circuits with all trunk circuits comprising a group nor-' mally interconnecting other stations.

i. In a telephone system, a plurality of switching-points, a group of trunk circuits extending from each switchingpoint to another, link circuits at each switching point for connection with the trunk circuits extending therefrom, a relay associated with each trunk circuit at a switching point operating upon the connection of a link circuit with the trunk circuit, the contacts of the relays for all trunk circuits of a group being serially interconnected, and signaling means at another station responsive to the contemporaneous closure of the serially in terconnected contacts associated with a grouo of trunk circuits. I

5. n a telephone system, a plurality oi switching points, a group of trunk circuits extending from each switching point to another, link circuits at each switching point for, interconnecting the trunk circuits ex-i tending therefrom to form athrough trunk line circuit interconnecting normally disconnected switching points, a relay at each switching point associated with each trunk circuit controlled by the connection of a link circuit with; the associated trunk circuit, and signaling means at a normally disconnected switching point controlled by the cooperation of relays at an intermediate switching point. p

6. In a telephone system, a pluralityoi exchanges, a plurality of trunk circuits for establishing connections between said exchanges, and means at each exchange for indicating the condition of the trunk circuits interconnecting other exchanges.

7. In a telephone system, a series of exchanges, a plurality of trunk circuits for establishing connections from any one of said exchanges to each of the other exchanges and means at each exchange for indicating the condition of trunk circuits interconnecting any other two exchanges of the series. f

In witness whereof we hereunto subscribe our names this 8th day of Ma A. D. 1918.

' HEN-RY P. CLAUSEN.

CHARLES L. GOQDRUM. 

